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GCN Circular 22154

GRB 171123A: MITSuME Akeno optical upper limits
2017-11-24T07:02:25Z (6 years ago)
Katsuhiro L. Murata at Nagoya U <>
K. Morita, R. Itoh, K. L. Murata, T. Yoshii, Y. Tachibana, S. Harita, T.
Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 171123A (P. A. Evans  et
al., GCN Circular #22148) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.
The observation started on 2017-11-23 16:24:30.61 UT. We did not find any
new point source within enhanced XRT circle (M.R. Goad et al., GCN Circular
#22150) in all three bands.
We obtained following limits for the magnitudes.

T0+[hour]    MID-UT      T-EXP[sec]    g'       Rc        Ic
~3.15       18:56:14.59      9360     >21.1    >20.7     >19.6

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
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